Layered V2O5/PEDOT Nanowires and Ultrathin Nanobelts Fabricated with a Silk Reelinglike Process

For the first time, a method resembling a cocoon-to-silk fiber reeling process is developed to fabricate layered V2O5/PEDOT nanowires (VP NWs) by stirring V2O5 powder in an aqueous solution of 3,4-ethylenedioxythiophene (EDOT). A mechanistic study indicates that the growth of VP NWs started from the intercalation/polymerization of EDOT within a few V2O5 surface layers, which were then peeled off to produce nanowires. The resulting VP NWs were further exfoliated to form 3.8 nm ultrathin V2O5/PEDOT nanobelts (VP NBs) consisting of V2O5 atomic bilayers intercalated with PEDOT. These VP NBs can be dispersed well in various solvents including water, ethanol, DMF, and acetonitrile for the preparation of transparent thin films as the hole extraction layer (HEL) to replace PEDOT:PSS in solution-processed inverted planar perovskite solar cells (PSCs). Cell efficiency tests over 7 days revealed that PSCs fabricated with VP NBs as HEL retained the initial power conversion efficiency (PCE), while those with PEDOT:PSS as HEL suffered from an efficiency drop of more than 50%.